Industrial paper sack of the valve type

ABSTRACT

An industrial paper sack of the valve type, includes a tubular side wall extending along a longitudinal axis, a first bottom arranged on one side of the tubular side wall along a direction parallel to the longitudinal axis and a second bottom arranged on an opposite side with respect to the first bottom along the direction parallel to the longitudinal axis. The first bottom includes a filling opening of the sack, configured to be sealed after the filling of the sack. The second bottom is folded at a first folding line to form a first folded bottom portion and includes, at a free end of the first folded bottom portion, an emptying opening of the sack. The first folded bottom portion is coupled to the tubular side wall by a removable coupling device.

FIELD OF THE INVENTION

The present invention relates to an industrial paper sack of the valvetype.

BACKGROUND

Industrial paper sacks are typically used to package and transport bulkmaterials of different type, in particular food (e.g., flour), chemical(e.g., granules of plastic material), construction (e.g., cement),agricultural (e.g., seeds), zootechnical (e.g., feed) material, etc.

Industrial paper sacks are divided into two types: sacks of the opentype and sacks of the valve type.

The sacks of the open type typically comprise a tubular side wallextending along a longitudinal axis, a closed bottom arranged on oneside of the tubular side wall and an end portion arranged on theopposite side of the tubular side wall, said end portion being open toallow the filling of the sack, re-closable upon completed filling andpossibly re-openable to allow the emptying of the sack.

Instead, the sacks of the valve type typically comprise a tubular sidewall extending along a longitudinal axis, a first bottom arranged on oneside of the tubular side wall and a second bottom arranged on the otherside of the tubular side wall.

The first bottom comprises a filling opening (called in technical jargon“valve”) intended to be closed after filling the sack, while the secondbottom comprises an emptying opening which, during the filling of thesack, is closed and which is then opened in order to be able to emptythe sack.

In order to avoid contamination of the material contained within thesack by external agents, the valve is sealed upon having filled thesack.

The Applicant has focused his attention on the sacks of the valve type.

The Applicant has noted that in this type of sacks the emptying openingis closed for example by gluing or thermal/ultrasonic welding of thepaper. When the sack has to be emptied, the user opens the emptyingopening by tearing the glued or welded paper.

The Applicant has noted that this opening mode involves severaldrawbacks.

First of all, at the time of opening the sack, defibrations and/or tornpaper and/or glue and/or any other agents present in the externalenvironment could come into contact with the material contained in thesack, with consequent risks of contamination of the material.

In addition, during the sack opening operations, the user’s hands cancome into contact with the material contained in the sack, withconsequent risks also for the user (depending on the type of material),further to the risk of contamination of the material itself.

It may also happen that the tearing of the glued or welded paper isdifficult for some users, with the risk of damaging the sack andspilling a part of the material contained in the sack on the ground.

The problem underlying the present invention is to make an industrialpaper sack of the valve type that overcomes the drawbacks discussedabove.

SUMMARY

The present invention therefore relates to an industrial paper sack ofthe valve type, comprising a tubular side wall extending along alongitudinal axis, a first bottom arranged on one side of the tubularside wall along a direction parallel to the longitudinal axis and asecond bottom arranged on an opposite side with respect to the firstbottom along the direction parallel to the longitudinal axis, whereinthe first bottom comprises a filling opening of the sack configured tobe sealed after the filling of the sack and wherein the second bottom isfolded at a first folding line to form a first folded bottom portion andcomprises, at a free end of said first folded bottom portion, anemptying opening of the sack, wherein said first folded bottom portionis coupled to said tubular side wall through a removable couplingdevice.

In the sack of the invention access to the material contained in thesack can only take place after removing the removable coupling deviceand unfolding the folded first bottom portion. This avoids the risks ofcontamination of the material in the sack and the risks of accidentalcontact between the material and the user. This is particularlyadvantageous when the sack contains e.g., food and/or chemical material.

Thanks to the provision of the removable coupling device, the sack isnot damaged during the opening thereof and it is possible to close itagain by folding it at the first folding line, thus being able to dosethe amount of material removed from the sack from time to time. This isparticularly advantageous when the sack contains, for example,agricultural and zootechnical material.

Preferred characteristics of the sack of the present invention aredescribed below. Such characteristics may be provided individually or incombination with each other, unless explicitly stated otherwise.

Preferably, the second bottom is further folded at a second folding lineto form a second folded bottom portion, said second folded bottomportion being connected to the first folded bottom portion at the firstfolding line.

More preferably, said removable coupling device is active between saidsecond folded bottom portion and said tubular side wall.

In this way, access to the material contained in the sack can only takeplace after unfolding the sack first at the second folding line andsubsequently at the first folding line, thus further reducing theaforementioned risks of contamination of, and of accidental contactwith, the material contained in the sack.

Preferably, the removable coupling device is formed on a patchassociated with said second folded bottom portion and with said tubularside wall.

The patch is preferably made of paper and may have the same dimensionsas or slightly smaller or slightly larger dimensions than those of thesecond bottom and/or of the tubular side wall.

Preferably, the patch is glued to said second folded bottom portion andto said tubular side wall.

Preferably, the removable coupling device comprises a tear tab.

Opening the sack therefore requires the user to grasp the tab at an endportion thereof, suitably indicated on the sack (for example with anarrow), and then to lift and tear it away from the sack.

The tear tab is preferably formed on the patch.

Preferably, the tear tab is overlapped to said first folding line.

More preferably, when the tear tab is torn, it separates the patch intwo opposite portions, one of which remains associated with said secondfolded bottom portion and the other one remains associated with saidtubular side wall. In this way, after the tear tab has been torn off,the user can unfold the second folded bottom portion at the secondfolding line and subsequently the first folded bottom portion at thefirst folding line, allowing the sack to be emptied through the emptyingopening.

Preferably, said first folding line is substantially orthogonal to thelongitudinal axis.

Preferably, said second folding line is substantially orthogonal to thelongitudinal axis.

Preferably, said tubular side wall is joined at a gluing line extendingalong a direction substantially parallel to the longitudinal axis.

Preferably, the sack comprises a front face and a rear face mutuallyglued at two end portions of the second bottom, said end portions beingarranged on opposite sides with respect to the longitudinal axis of thesack.

In this way, when the sack is full it takes on a stiffer and moredefined shape.

Preferably, said filling opening is sealed by thermal or ultrasonicwelding.

This type of sealing allows the filling opening to be sealed without thesupply of welding material. It also prevents leakages of the materialcontained in the sack after its filling. This is particularly usefulwhen the sack, during handling and use, is repeatedly placed to rest onthe first bottom.

Preferably, a coating layer is placed around said filling opening.

The coating layer may be of plastic material or of another kind and maybe coupled to a layer of paper arranged around the filling opening bygluing or spreading. Alternatively, the coating layer may be co-extrudedwith the layer of paper arranged around the filling opening. Such acoating layer allows the filling opening to be closed by thermal orultrasonic welding.

Preferably, said tubular side wall comprises a plurality of overlappedlayers.

Preferably, said overlapped layers are all made of paper.

Alternatively, at least one of said overlapped layers is made of plasticmaterial. The layer in plastic material prevents moisture from enteringthe sack.

Preferably, in this case, the plastic layer is arranged internally to alayer of paper or interposed between two layers of paper.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention willbecome clearer from the following detailed description of preferredembodiments thereof, made with reference to the appended drawings andprovided by way of indicative and non-limiting example. In suchdrawings:

FIG. 1 is a plan view of an industrial paper sack of the valve type inaccordance with the present invention in a first operating configurationthereof (sack closed with removable coupling device not removed);

FIG. 2 is a plan view of the sack of FIG. 1 in a second operatingconfiguration thereof (sack closed with removable coupling deviceremoved);

FIG. 3 is a plan view of the sack of FIG. 1 in a third operatingconfiguration thereof (partially unfolded sack);

FIG. 4 is a plan view of the sack of FIG. 1 in a fourth operatingconfiguration thereof (fully unfolded sack).

DETAILED DESCRIPTION

In FIGS. 1-4 , an industrial paper sack of the valve type in accordancewith the present invention is indicated with reference numeral 10.

The sack 10 comprises a tubular side wall 20 extending along alongitudinal axis X.

A first bottom 30 and a second bottom 40 are formed on opposite sides ofthe tubular side wall 20 with respect to a direction parallel to thelongitudinal axis X.

In FIGS. 1-4 the sack 10 is shown when it is empty, i.e., when it hasnot yet been filled. The filling material may be of different type, forexample flour if the sack 10 is intended for use in the food field,granules of plastic material if the sack 10 is intended for use in thechemical field, cement if the sack 10 is intended for use in theconstruction field, seeds if the sack 10 is intended for use in theagricultural field, feeds if the sack 10 is intended for use in thezootechnical field, etc.

In FIGS. 1-4 the sack 10 is shown in a flattened configuration thereof.

The sack 10 comprises a front face 11 and a rear face, wherein the term“front” is used to refer to the visible face of FIGS. 1-4 and the term“rear” is used to refer to the hidden face in FIGS. 1-4 .

The tubular side wall 20 is formed starting from a sheet of paper, orfrom a plurality of overlapped layers of paper, which is/are wrappedaround the longitudinal axis X to form a tubular structure. The tubularside wall 20 is joined at a gluing line 22 extending along a directionsubstantially parallel to the longitudinal axis X. In the case ofseveral overlapped layers, different gluing lines may be provided foreach layer, the gluing lines possibly being staggered with respect toeach other.

In the non-limiting example shown in FIGS. 1-4 , the gluing line 22 isprovided on the rear side of the sack 10.

In the case of multiple overlapped layers, they are connected to eachother (e.g., glued) at respective joining portions. A layer made ofplastic material may also be provided, such a layer being overlapped onone or more layers of paper and being arranged internally to a layer ofpaper or interposed between two layers of paper. The layer of plasticmaterial may also be more than one, in which case each of them isinterposed between two respective layers of paper.

The first bottom 30 is formed by conveniently folding a first endportion 30 a of the sack 10 and by applying, for example by gluing, afirst patch 33 to the folded end portion 30 a, the first patch 33 beingpreferably made of paper. In the non-limiting example of FIGS. 1-4 , thefirst patch 33 has a rectangular shape.

The first patch 33 actually provides the first bottom 30 with aflattened and sufficiently stiff shape, suitable to allow the sack 10 tostand when filled and resting on the ground or on a horizontal plane atthe first bottom 30.

The first bottom 30 comprises a filling opening 32 of the sack 10, whichdefines the so-called valve of the sack 10 and which is configured to besealed after the filling of the sack 10.

The sealing takes place by thermal welding (in this case, the valve iscalled “heat-sealing valve”) or ultrasonic welding.

To allow sealing, a coating layer 34, preferably made of plasticmaterial, is placed inside the sack 10 around the filling opening 32.

In particular, the coating layer is glued to a layer of paper arrangedaround the filling opening 32.

The second bottom 40 comprises an emptying opening 42 of the sack 10(FIG. 4 ). The emptying opening 42 is substantially orthogonal to thelongitudinal axis X.

The second bottom 40 is folded at a first folding line 44 so as to forma first folded bottom portion 43 (FIG. 3 ), and subsequently the firstfolded bottom portion 43 is folded at a second folding line 46 so as toform a second folded bottom portion 45 (FIGS. 1 and 2 ).

The first folding line 44 is substantially orthogonal to thelongitudinal axis X and thus substantially parallel to the emptyingopening 42.

The first folding line 44 is arranged at a predetermined distance A fromthe emptying opening 42 (FIG. 4 ).

The first folded bottom portion 43 is defined between the first foldingline 44 and the emptying opening 42 (FIG. 3 ).

The emptying opening 42 is defined at a free end of the first foldedbottom portion 43, which corresponds to a free end of the sack 10 in itsinitial shape, before forming the second bottom 40 (FIG. 4 ).

The second folding line 46 is substantially orthogonal to thelongitudinal axis X and thus substantially parallel to the first foldingline 44.

The second folding line 46 is arranged at a predetermined distance Bfrom the first folding line 44 (FIGS. 3 and 4 ).

The second folded bottom portion 45 is defined between the first foldingline 44 and the second folding line 46 (FIGS. 1 and 2 ). The secondfolded bottom portion 45 is connected to the first folded bottom portion43 at the first folding line 44.

The distance A is less than or equal to the distance B.

The second bottom 40 comprises a removable coupling device 48 configuredto couple the second folded bottom portion 45, or the first foldedbottom portion 43 in cases where the second folding is not provided atthe second folding line 46, to the tubular side wall 20.

The removable coupling device 48 is formed on a second patch 50associated with the second bottom 40, in particular with the secondfolded bottom portion 45, and with the tubular side wall 20.

The removable coupling device 48 comprises a tear tab 52 overlapped onthe first folding line 44 and on the tubular side wall portion 20adjacent to the first folded bottom portion 43, when the first foldedbottom portion 43 is folded like in FIGS. 1 and 2 .

The tear tab 52 has an end portion 53 adapted to be grasped by the userto lift it and tear it away from the second patch 50. The end portion 53is indicated for example by a line drawn on the second patch 50 so thatit is immediately identified by the user.

When the tear tab 52 is torn (FIG. 2 ), it separates the second patch 50in two opposite portions 50 a and 50 b. The portion 50 a is adjacent, onthe one hand, to the first folding line 44 and, on the other hand, tothe second folding line 46. The portion 50 a remains associated with thesecond folded bottom portion 45, while the portion 50 b remainsassociated with the tubular side wall 20.

In the embodiment shown in the attached figures, the second patch 50 hasslightly smaller dimensions than those of the second bottom 40. Thesecond patch 50 is preferably made of paper and is glued to the secondbottom 40.

In other embodiments, not shown, the second patch 50 may havesubstantially the same or slightly larger dimensions than those of thesecond bottom 40 and/or of the tubular side wall 20.

In the non-limiting example of FIG. 1 , the second bottom 40 and thesecond patch 50 are rectangular in shape. In particular, the secondpatch 50 has a width slightly smaller than that of the second bottom 40.

In order to provide the filled sack 10 with a stiffer and more definedshape, the front face 11 can be glued to the rear face of the sack 10 attwo end portions 24 of the second bottom 40. Such end portions 24 arearranged on opposite sides with respect to the longitudinal axis X.

Only after removing the tear tab 52 and unfolding the second bottom 40around the two folding lines 44 and 46 one can access to the materialcontained in the sack 10 and the removal of said material from the sack10 can take place through the emptying opening 42.

The sack 10 is not damaged following the removal of the tear tab 52 andit is possible, for example, to close it by folding the second bottom 40at the folding lines 44 and 46 and possibly by applying a new patch 50.

Obviously, in order to meet specific and contingent needs, a personskilled in the art may make numerous modifications and changes to thesack described above, all of which are within the scope of protection ofthe present invention as defined by the following claims.

For example, only one folding line could be provided instead of the twofolding lines 44, 46 of the non-limiting example of FIGS. 1-4 .

Or, more than two folding lines could also be provided.

The folded bottom portions 43, 45 of the second bottom 40 may be gluedto each other before emptying the sack 10. This arrangement can also beprovided in the case of the non-limiting example of FIGS. 1-4 .

The patches 33 and 50 may extend only on the front side or only on therear side or on both sides of the sack 10. In the non-limiting exampleof FIGS. 1-4 , the patches 22 and 50 extend only on the front side ofthe sack 10.

1. An industrial paper sack of a valve type, comprising a tubular sidewall extending along a longitudinal axis, a first bottom arranged on oneside of the tubular side wall along a direction parallel to thelongitudinal axis and a second bottom arranged on an opposite side withrespect to the first bottom along said direction parallel to thelongitudinal axis, wherein the first bottom comprises a filling openingof the sack configured to be sealed after the filling of the sack andwherein the second bottom is folded at a first folding line to form afirst folded bottom portion and comprises, at a free end of said firstfolded bottom portion, an emptying opening of the sack, wherein saidfirst folded bottom portion is coupled to said tubular side wall througha removable coupling device.
 2. The sack according to claim 1, whereinthe second bottom is further folded at a second folding line to form asecond folded bottom portion, said second folded bottom portion beingconnected to said first folded bottom portion at said first folding lineand wherein said removable coupling device is active between said secondfolded bottom portion and said tubular side wall.
 3. The sack accordingto claim 2, wherein said removable coupling device is formed on a patchassociated with said second folded bottom portion and with said tubularside wall.
 4. The sack according to claim 3, wherein said patch is gluedto said second folded bottom portion and to said tubular side wall. 5.The sack according to claim 1, wherein said removable coupling devicecomprises a tear tab.
 6. The sack according to claim 5, wherein saidremovable coupling device is formed on a patch associated with saidsecond folded bottom portion and with said tubular side wall, andwherein said tear tab is overlapped to said first fold line and, when itis torn, separates said patch in two opposite portions, one of the twoopposite portions remains associated with said second folded bottomportion and the other one of the two opposite portions remainsassociated with said tubular side wall.
 7. The sack according to claim1, wherein said first folding line is substantially orthogonal to thelongitudinal axis.
 8. The sack according to claim 1, wherein the secondbottom is further folded at a second folding line to form a secondfolded bottom portion, said second folded bottom portion being connectedto said first folded bottom portion at said first folding line andwherein said removable coupling device is active between said secondfolded bottom portion and said tubular side wall, and wherein saidsecond folding line is substantially orthogonal to the longitudinalaxis.
 9. The sack according to claim 1, comprising a front face and arear face mutually glued at two end portions of the second bottom, saidend portions being arranged on opposite sides with respect to thelongitudinal axis.
 10. The sack according to claim 1, wherein saidfilling opening is sealed by thermal or ultrasonic welding.